Lexicon DC-2 and DD-EX, DTS-ES

I have a Lexicon DC-2 (version 4.0 and fully loaded with the DD, DTS, and THX daughter boards) and a 7.1 speaker system. Looking at the display, I cannot tell if DolbyDigital-EX and DTS-ES encoded soundtracks are being properly decoded. According to the manual, I can get EX and ES decoding while in THX mode, but it makes no mention of any other decoding scheme (DD, DTS, L7, etc.) in this respect. Is there any way to assure EX and ES decoding in at least Logic 7, since that's what I almost always have it set to?

"According to the manual, I can get EX and ES decoding while in THX mode, but it makes no mention of any other decoding scheme (DD, DTS, L7, etc.) in this respect."

For DTS ES and THX Surround EX decoding you use the THX mode.

" there any way to assure EX and ES decoding in at least Logic 7, since that's what I almost always have it set to? "

If you are using EX/ES decoding your aren't using Logic 7 and vice versa. They are two different decoding processes. Remember that the material the ES/EX decoding would use is just common mono material in both surrounds. So L7 decoding will use that material too but it would treat it the same as any other mono material in your surround speakers.

DD-EX is delivered using regular DD 5.1. The surround back channel is just matrixed into the rear surrounds. Just like the center channel is on 2 channel Dolby Surround material. As such the material that a THX Surround EX decoder would send to surround back will be used by Logic 7. However it will use it differently then THX Surround EX decoding would.

" Will the DTS THX-EX mode work with both discrete and matrixed encoding?"

In the DC-2 it only has the matrix decoder not the discrete. However all DTS ES Discrete 6.1 sound tracks are also backwards compatible with DTS ES decoders... like what the DC-2 has. The matrix version works very much like the THX Surround EX mode on DD. And likewise Logic 7 on the DTS track would act the same way too.

"You are using THX EX decoding for both DD EX and DTS ES material. The DC-2 does not have official DTS-ES Discrete & Matrix decoding on board."

Actually the version that is in the MC-1 is official DTS-ES matrix decoding, just the original version of it. DTS later on changed the rear steering from a DPL type steering matrix to DTS NEO type steering.

If you have both side and rear surrounds and haven't turned THX-EX off, hitting the "THX" button will get you THX-EX in 5.1 and DTS modes (prior to DTS Neo and the marketting department having coronaries, DTS-ES matrix was DTS + Dolby THX-EX ).

If you've selected Logic-7, you get 5.1 Logic-7 or DTS Logic-7 as appropriate.

THX-EX has artifacts on some non-encoded pieces.

Logic-7 does not, and does a fine job at putting rear-center right behind you (as in The Haunting). So most Lexicon owners just use Logic-7 on everything...